Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 49817 — Cooks, MI

ZIP code 49817 (Cooks, Schoolcraft County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 16 and the first fall frost September 24.

Where ZIP 49817 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostMay 16

First frostSep 24

2012 zone5a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cooks, MI…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Cooks, MI

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 16median — 50% chance of a later frost

Safe for tender plantsJune 3only 10% chance of frost after

First fall frostSeptember 24median — 10% chance by Sep 1

Growing season129 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 3 and returns around October 7.

From the NOAA station Garden Corners, MI — 4 miles away, elevation 587 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 49817

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 4 – Apr 18

SpinachSow outdoors · Apr 4 – Apr 25

Broccoli, cabbageStart indoors · Mar 7 – Mar 21

Broccoli, cabbageTransplant · Apr 25 – May 9

Onion setsPlant outdoors · Apr 18 – May 2

PotatoesPlant outdoors · Apr 25 – May 9

LettuceSow outdoors · Apr 18 – May 2

Carrots, beetsSow outdoors · Apr 25 – May 9

TomatoesStart indoors · Mar 21 – Apr 4

TomatoesTransplant · May 23 – Jun 6

Peppers, eggplantStart indoors · Mar 7 – Mar 21

Peppers, eggplantTransplant · May 30 – Jun 13

BeansSow outdoors · May 23 – Jun 6

Sweet cornSow outdoors · May 23 – Jun 6

Cucumbers, squashSow outdoors · May 23 – Jun 6

Fall lettuce, spinachSow outdoors · Jul 30 – Aug 13

GarlicPlant cloves · Sep 10 – Oct 15

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 16) and first fall frost (Sep 24) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 49817 came on May 1 — about the same time as the 1991–2020 average (Apr 29).

average
Apr 292026
May 1

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 5a in Michigan

551 plants native to the lower 48 states, recorded in Michigan, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Cooks, MI.

Soil in Cooks, MI

The soil mapped at the center of ZIP 49817 is Kalkaska — moderately decomposed plant material, somewhat excessively drained.

TextureModerately decomposed plant materialtop layer

pH4.7strongly acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter70%high

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Kalkaska sand, 0 to 6 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 49817; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cooks, MI

Summer high78 °Faverage high, July

Winter low7 °Faverage low, February

Hot days1days a year at 90 °F or more

Freezing nights185nights a year at 32 °F or less

Growing degree days1,611base 50 °F — the season’s usable heat

Longest day15 h 45 mindaylight on June 21

Shortest day8 h 39 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation34.1 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Garden Corners, MI (4 mi away); precipitation: Garden Corners, MI (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

498645b

Nahma, MI · 10 mi

498545a

Manistique, MI · 12 mi

Rapid River, MI · 18 mi

Gladstone, MI · 28 mi

Michigan planting zones →

Questions about 49817

What planting zone is ZIP code 49817?

ZIP code 49817 (Cooks, MI) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Cooks, MI?

The median last spring frost (32 °F) near 49817 is May 16; after June 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Garden Corners station.

When is the first frost in Cooks, MI?

The median first fall frost near 49817 is September 24, giving a median frost-free growing season of 129 days.

When should I plant tomatoes in 49817?

Start tomato seeds indoors around Mar 21 – Apr 4 and set transplants outside around May 23 – Jun 6, one to three weeks after the median last frost.

How much rain and snow does 49817 get?

About 34.1 inches of precipitation a year (NOAA 1991–2020 normals, Garden Corners station).

How hot do summers get in Cooks, MI?

The average high peaks at 78 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 49817 have?

The USDA soil survey maps Kalkaska at the center of ZIP 49817: moderately decomposed plant material, somewhat excessively drained, pH about 4.7 (strongly acidic).

Did spring come early in Cooks, MI in 2026?

Spring leaf-out near 49817 came on May 1 in 2026, about the same as the 1991–2020 average (Apr 29), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cooks, MI?

Long-day onions: the longest day near 49817 is 15 h 45 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).